In a random access network of a radio communication network, an address of a radio communication apparatus (hereinafter referred to as “device”) is an ID (identification code) that uniquely designates the radio communication apparatus, fulfilling the role of a “name”, so to speak. Generally, a LAN-type address is assigned a specific ID called a MAC address by the IEEE that differs for each product of each manufacturer. A device performs communication by specifying a communicating party based on this MAC address.
Current MAC addresses have a 48-bit address field. This is 16 bits longer than an Internet Version 4 address field, and therefore enables assignment to more apparatuses. However, even a 48-bit address field will not meet the future demand for MAC addresses, and therefore the use of EUI-64 providing a 64-bit address is planned.
Thus, addresses assigned to apparatuses are becoming ever longer. However, a problem when processing is performed on a LAN-type network using such an address, especially in the case of a wideband communication network for implementing large-volume communication, is that an address becomes an overhead. And as a result of this, there is a problem of the frame length for a control protocol that performs radio communication protocol maintenance becoming long.
With the WiMedia MAC protocol (see Non-patent Document 1 for details) that actually utilizes microwave UWB (Ultra Wide Band), communication is performed using an address system having a separate mode called a device address (also abbreviated to “DevAddr”, and hereinafter referred to simply as “address”), 2 bytes in length, in addition to a MAC address that performs authentication management of a device. This is a technique for reducing MAC address overhead.
The address system is as described below. A 16-bit address excluding a special multicast address or the like is installed arbitrarily in the local apparatus. If the source address of a received frame, or a BPOIE (Beacon Period Occupation Information Element) described later herein contains the same address, a value that does not duplicate a device ID that can be recognized by another beacon or BPOIE is calculated and re-set.
A BPOIE is information contained in a beacon for confirming mutual device recognition when all devices participating in a radio network align and transmit beacons in order to measure super-frame synchronization on an autonomous distributed network. At this time, information indicating that a beacon of device A is present in the X'th slot is transmitted among a plurality of devices. If a particular device recognizes that its own address is not written in even one slot that it transmits itself, that device considers that a duplication (collision) has occurred, and shifts to a different slot. As a result, that device can acquire a list of addresses of nearby or next-nearby devices, which helps in deciding a slot in which its own beacon is transmitted.
Non-patent Document 1: Yunpeng Zang et. al., “Towards High Speed Wireless personal Area Network-Efficiency Analysis of MBOA MAC,” http://www.ctr.kcl.ac.uk/IWWAN2005/papers/88_invited_Philips.pdf